Set sometime between season 3 and 4:
Arthur struggled helplessly against his bonds. It had all happened so quickly. One moment, he and Merlin had been on a routine hunt, sniping and arguing as they always were. They had been enjoying the outing, the short reprieve from the pressure of Camelot and the duties she held for them both.
Then, so rapidly, it had all turned sour. Seven men, armed to the tooth with crossbows, maces, and swords had come from them at all sides. Arthur had lost no time drawing his own sword from his horse, but these men had both numbers and the element of surprise on their side. Arthur had been fighting off four of them when he heard the pained cry behind him. A cry he had heard far too often lately.
The sight that met his eyes made him ill.
Merlin had crumpled to the ground in front of two men, while a third was already on the ground a few meters away, stroke down by a tree branch (Arthur would think about that later). Embedded in Merlin's side was a knife, handle gleaming as the sun hit it. The men were sporting ugly grins as they watched the manservant struggle for breath.
Arthur let out a roar of anger and charged at them, sword raised threateningly. But there were still four other bandits, and even the Crown Prince of Camelot was not match for six grown and ruthless men. They overwhelmed him and disarmed him, finally subduing him long enough to tie him to a tree.
Merlin had been left on the ground, unconscious and pale. The bandits took no notice of him, stepping around him as they looted Arthur's bags and planned their next move regarding the captured prince.
Arthur knew he should be listening, to try and find out their plan and use that knowledge to escape, but his attention was taken up entirely by Merlin. The boy's breathing had become less noticeable, and dark thoughts began to enter the prince's head unwillingly.
He knew he wouldn't be able to escape with Merlin in this condition, and there was no way he could leave the loyal idiot behind. So he was stuck, waiting for a rescue that might not have even begun yet.
One of the bandit's glanced over at Arthur, and noticed the worried stare the blonde boy trained on his manservant. He chuckled darkly, making his way over where the injured man lay and grabbed his pale chin, noting the faint and slow movement of his chest. He made a noise of mock sympathy before meeting Arthur's eyes.
"Such a shame- he was so young too" the bandit laughed and dropped Merlin's head back onto the ground, smirking at Arthur.
The glare Arthur gave him was mute fury and anger, and promised the bandit pain upon imagination. When the bandit turned his back, Arthur returned his gaze to Merlin, watching his chest rise and fall with increasing worry.
Just hold on a little longer, Merlin, Arthur pleaded as he scanned the forest, listening for a rescue.
Thanks for reading, and review and request are encouraged! ;)